Added the Model Comparison assistant for blind comparisons of two models (#1009)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/Tests/Assistants/ModelComparison/ModelComparisonTallyTests.cs

@@ -0,0 +1,61 @@
+using AIStudio.Assistants.ModelComparison;
+
+namespace AIStudio.Tests.Assistants.ModelComparison;
+
+/// <summary>
+/// Checks how the choices of several runs are counted.
+/// </summary>
+[TestFixture]
+public sealed class ModelComparisonTallyTests
+{
+    [Test]
+    public void NoRunsCountNothing()
+    {
+        var tally = ModelComparisonTally.Of([]);
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(tally.TotalRunCount, Is.Zero);
+            Assert.That(tally.ScoredRunCount, Is.Zero);
+            Assert.That(tally.UnscoredRunCount, Is.Zero);
+            Assert.That(tally.FirstModelWins, Is.Zero);
+            Assert.That(tally.SecondModelWins, Is.Zero);
+            Assert.That(tally.Ties, Is.Zero);
+        }
+    }
+
+    [Test]
+    public void EveryChoiceCountsForItsModel()
+    {
+        var tally = ModelComparisonTally.Of(
+        [
+            ModelComparisonModelChoice.FIRST,
+            ModelComparisonModelChoice.SECOND,
+            ModelComparisonModelChoice.FIRST,
+            ModelComparisonModelChoice.TIE,
+        ]);
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(tally.TotalRunCount, Is.EqualTo(4));
+            Assert.That(tally.ScoredRunCount, Is.EqualTo(4));
+            Assert.That(tally.FirstModelWins, Is.EqualTo(2));
+            Assert.That(tally.SecondModelWins, Is.EqualTo(1));
+            Assert.That(tally.Ties, Is.EqualTo(1));
+        }
+    }
+
+    [Test]
+    public void ARunWithoutAChoiceCountsOnlyTowardTheTotal()
+    {
+        var tally = ModelComparisonTally.Of([ModelComparisonModelChoice.SECOND, null, null]);
+
+        using (Assert.EnterMultipleScope())
+        {
+            Assert.That(tally.TotalRunCount, Is.EqualTo(3), "Every run happened.");
+            Assert.That(tally.ScoredRunCount, Is.EqualTo(1), "Only one run had a choice.");
+            Assert.That(tally.UnscoredRunCount, Is.EqualTo(2));
+            Assert.That(tally.SecondModelWins, Is.EqualTo(1));
+        }
+    }
+}